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Flashcards in B3 Deck (50)
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What is osmosis

Net movement of water from an area of higher water potential to an area of lower water potential

Diffusion of water
Down a concentration gradient
Across a partially permeable membrane


What is a turgid cell?

Water enters by osmosis, vacuole swells and pushes against cell wall


What is a flaccid cell?

Water lost from cell, vacuole shrinks, cell loses shape


What is active transport?

Does require energy
Particles move against a concentration gradient
Movement of particles from an area of lower concentration to an area of higher concentration-therefore it requires energy
The energy is needed to make "pumps" move particles the wrong way
Movement of substances against a concentration gradient across a partially permeable membrane


What is diffusion?

Net movement of particles from an area of higher concentration to lower concentration area

Down a concentration gradient (difference in number of particles on either side)


What affects the rate of diffusion?

Surface area
Concentration gradient
Thickness of gas exchange surface


How is the blood capillary involved in diffusion in the gut?

Dense capillary network-inside each villus are many capillaries which take away the absorbed molecules


How is the epithelial membrane involved in diffusion in the gut?

Is a thin layer(only one cell thick). This provides a short diffusion path for digested food molecules


How is the lacteal involved in diffusion in the gut?

At the centre of the villus absorbed fats and carries them away from the villus. This maintains concentration gradient for absorption


Why does the rate of active transport depends on the rate of respiration, why?

As more respiration occurs, more energy is available and therefore more active transport takes place


State the ventilation path

Nose + mouth


What is ventilation?

Scientific term for breathing where air is constantly moving in and out of the lungs


What is inspiration?

Occurs when air pressure in the atmosphere is greater than that of the lungs forcing the air into the alveoli


What is expiration?

Occurs when air pressure in the lungs is greater than that in the atmosphere forcing air out the alveoli


What are xylem?

Cells that transport water and minerals up the stem from the roots to the shoots and leaves. This transport occurs in one direction only


What is phloem

Cells transport sugars produced in the leaves up and down the stem to growing and storage tissues


How are the phloem and xylem arranged

In plants as vascular bundles
Both form continuous systems connecting roots, stems and leaves


What is transpiration

The release of water vapour from a plant through the leaves causing water to move through the plant


What is stage one of transpiration

Water diffuses through osmosis from soil to roots
Roots are covered in tiny projections called root hair cells
These structures increase the surface area of he roots and therefore increases the rate of water up take/ diffusion by osmosis


What is stage two of transpiration

Water travels up the stem in the xylem
It diffuses from an area of high concentration to an area of low concentration
It's higher in the roots because that's where the water is absorbed it's lower in the leaves because it's used for photosynthesis


What is stage three of transpiration

Water travels through veins into leaves. It then diffuses out of the veins and into cells and from these airspaces, water diffuses by osmosis through the stomata into the air where it is evaporated


What is stage four of transpiration

The loss of water through transpiration in the leaves sets up a concentration gradient, continuously pulling water from the soul into all parts of the plant. Capillary action also encourages the water movement up the plant


What factors affect transpiration

Light intensity


What makes up the blood

White blood cells
Red blood cells


What are blood vessels

Arteries carry blood away from the heart (high pressure)
Carry oxygenated blood
Thick muscular walls
Small lumen
Has a pulse
No valves


What are Capillaries?

Penetrate all tissues
Very narrow
Allows transport of oxygen and nutrients into body cells and water out of cells


What are veins?

Carry blood towards the heart
Low pressure
Carry deoxygenated blood
Thinner more flexible walls
Large lumen
Doesn't have a pulse
Valves present


What's homeostasis

Maintaining internal body conditions


What are kidneys

Proteins digested by amino acids and absorbed by blood
Excess amino acid carried in the blood to the liver
Your liver cells convert them to ammonia
The ammonia reacts with the carbon dioxide to make urea
The urea passes through the kidneys to be removed from the body as urine


What's the role of the kidneys

Help clean the blood